Abstract: The invention provides semiconductor structure comprising a strained Ge channel layer, and a gate dielectric disposed over the strained Ge channel layer. In one aspect of the invention, a strained Ge channel MOSFET is provided. The strained Ge channel MOSFET includes a relaxed SiGe virtual substrate with a Ge content between 50-95%, and a strained Ge channel formed on the virtual substrate. A gate structure is formed upon the strained Ge channel, whereupon a MOSFET is formed with increased performance over bulk Si. In another embodiment of the invention, a semiconductor structure comprising a relaxed Ge channel layer and a virtual substrate, wherein the relaxed Ge channel layer is disposed above the virtual substrate. In a further aspect of the invention, a relaxed Ge channel MOSFET is provided. The method includes providing a relaxed virtual substrate with a Ge composition of approximately 100% and a relaxed Ge channel formed on the virtual substrate.

Abstract: The method for forming wavelike coherent nanostructures by irradiating a surface of a material by a homogeneous flow of ions is disclosed. The rate of coherency is increased by applying preliminary preprocessing steps.

Abstract: A method to form a strain-inducing semiconductor region is described. In one embodiment, formation of a strain-inducing semiconductor region laterally adjacent to a crystalline substrate results in a uniaxial strain imparted to the crystalline substrate, providing a strained crystalline substrate. In another embodiment, a semiconductor region with a crystalline lattice of one or more species of charge-neutral lattice-forming atoms imparts a strain to a crystalline substrate, wherein the lattice constant of the semiconductor region is different from that of the crystalline substrate, and wherein all species of charge-neutral lattice-forming atoms of the semiconductor region are contained in the crystalline substrate.

Abstract: A semiconductor device system, structure, and method of manufacture of a source/drain to retard dopant out-diffusion from a stressor are disclosed. An illustrative embodiment comprises a semiconductor substrate, device, and method to retard sidewall dopant out-diffusion in source/drain regions. A semiconductor substrate is provided with a gate structure, and a source and drain on opposing sides of the gate structure. Recessed regions are etched in a portion of the source and drain. Doped stressors are embedded into the recessed regions. A barrier dopant is incorporated into a remaining portion of the source and drain.

Abstract: Highly uniform silica nanoparticles can be formed into stable dispersions with a desirable small secondary particle size. The silica particles can be surface modified to form the dispersions. The silica nanoparticles can be doped to change the particle properties and/or to provide dopant for subsequent transfer to other materials. The dispersions can be printed as an ink for appropriate applications. The dispersions can be used to selectively dope semiconductor materials such as for the formation of photovoltaic cells or for the formation of printed electronic circuits.

Abstract: Disclosed is a transistor that incorporates epitaxially deposited source/drain semiconductor films and a method for forming the transistor. A crystallographic etch is used to form recesses between a channel region and trench isolation regions in a silicon substrate. Each recess has a first side, having a first profile, adjacent to the channel region and a second side, having a second profile, adjacent to a trench isolation region. The crystallographic etch ensures that the second profile is angled so that all of the exposed recess surfaces comprise silicon. Thus, the recesses can be filled by epitaxial deposition without divot formation. Additional process steps can be used to ensure that the first side of the recess is formed with a different profile that enhances the desired stress in the channel region.

Abstract: Various embodiments of the invention relate to a CMOS device having (1) an NMOS channel of silicon material selectively deposited on a first area of a graded silicon germanium substrate such that the selectively deposited silicon material experiences a tensile strain caused by the lattice spacing of the silicon material being smaller than the lattice spacing of the graded silicon germanium substrate material at the first area, and (2) a PMOS channel of silicon germanium material selectively deposited on a second area of the substrate such that the selectively deposited silicon germanium material experiences a compressive strain caused by the lattice spacing of the selectively deposited silicon germanium material being larger than the lattice spacing of the graded silicon germanium substrate material at the second area.

Abstract: An integrated circuit (“IC”) fabricated on a semiconductor substrate has an active gate structure formed over a channel region in the semiconductor substrate. A dummy gate structure is formed on a dielectric isolation structure. The dummy gate structure and the active gate structure have the same width. A sidewall spacer on the dummy gate structure overlies a semiconductor portion between a strain-inducing insert and the dielectric isolation structure.

Abstract: Semiconductor structures and devices including strained material layers having impurity-free zones, and methods for fabricating same. Certain regions of the strained material layers are kept free of impurities that can interdiffuse from adjacent portions of the semiconductor. When impurities are present in certain regions of the strained material layers, there is degradation in device performance. By employing semiconductor structures and devices (e.g., field effect transistors or “FETs”) that have the features described, or are fabricated in accordance with the steps described, device operation is enhanced.

Abstract: A p-type MOSFET of a CMOS structure has a silicon-germanium alloy channel to which a longitudinal compressive stress is applied by embedded epitaxial silicon-germanium alloy source and drain regions comprising a silicon-germanium alloy having a higher concentration of germanium than the channel of the p-type MOSFET. An n-type MOSFET of the CMOS structure has a silicon-germanium alloy channel to which a longitudinal tensile stress is applied by embedded epitaxial silicon source and drain regions comprising silicon. The silicon-germanium alloy channel in the p-type MOSFET provides enhanced hole mobility, while the silicon-germanium alloy channel in the n-type MOSFET provides enhanced electron mobility, thereby providing performance improvement to both the p-type MOSFET and the n-type MOSFET.

Abstract: An intermediate product in the manufacture of a vertical multiple-channel FET device containing alternating —Si—[(SiGe)—Si]u- stacked layers is shown, as well as a process for selectively etching the SiGe layers in such a stacked layer system, and products obtained from such selective etching. Differential Ge content is added to the successive layers to provide uniform removal of the sacrificial SiGe layers.

Abstract: A lateral heterojunction bipolar transistor (HBT) is formed on a semiconductor-on-insulator substrate. The HBT includes a base including a doped silicon-germanium alloy base region, an emitter including doped silicon and laterally contacting the base, and a collector including doped silicon and laterally contacting the base. Because the collector current is channeled through the doped silicon-germanium base region, the HBT can accommodate a greater current density than a comparable bipolar transistor employing a silicon channel. The base may also include an upper silicon base region and/or a lower silicon base region. In this case, the collector current is concentrated in the doped silicon-germanium base region, thereby minimizing noise introduced to carrier scattering at the periphery of the base. Further, parasitic capacitance is minimized because the emitter-base junction area is the same as the collector-base junction area.

Abstract: A recess along a sidewall is formed in a pMOS region and an nMOS region. An SiC layer of which thickness is thicker than a depth of the recess is formed in the recess. A sidewall covering a part of the SiC layer is formed at both lateral sides of a gate electrode in the pMOS region. A recess is formed by selectively removing the SiC layer in the pMOS region. A side surface of the recess at the gate insulating film side is inclined so that the upper region of the side surface, the closer to the gate insulating film in a lateral direction at a region lower than the surface of the silicon substrate. An SiGe layer is formed in the recess in the pMOS region.

Abstract: Techniques are disclosed for forming a non-planar germanium quantum well structure. In particular, the quantum well structure can be implemented with group IV or III-V semiconductor materials and includes a germanium fin structure. In one example case, a non-planar quantum well device is provided, which includes a quantum well structure having a substrate (e.g. SiGe or GaAs buffer on silicon), a IV or III-V material barrier layer (e.g., SiGe or GaAs or AlGaAs), a doping layer (e.g., delta/modulation doped), and an undoped germanium quantum well layer. An undoped germanium fin structure is formed in the quantum well structure, and a top barrier layer deposited over the fin structure. A gate metal can be deposited across the fin structure. Drain/source regions can be formed at respective ends of the fin structure.

Abstract: A field effect transistor according to an embodiment includes: a semiconductor layer; a source region and a drain region formed at a distance from each other in the semiconductor layer; a gate insulating film formed on a portion of the semiconductor layer, the portion being located between the source region and the drain region; a gate electrode formed on the gate insulating film; and a gate sidewall formed on at least one of side faces of the gate electrode, the side faces being located on a side of the source region and on a side of the drain region, the gate sidewall being made of a high dielectric material. The source region and the drain region are separately-placed from the corresponding side faces of the gate electrode.

Abstract: The present disclosure relates to the field of fabricating microelectronic devices. In at least one embodiment, the present disclosure relates to forming an isolated nanowire, wherein isolation structure adjacent the nanowire provides a substantially level surface for the formation of microelectronic structures thereon.

Abstract: The lattice mismatching between a Ge layer and a Si layer is as large as about 4%. Thus, when the Ge layer is grown on the Si layer, penetration dislocation is introduced to cause leakage current at the p-i-n junction. Thereby, the photo-detection sensitivity is reduced, and the reliability of the element is also lowered. Further, in the connection with a Si waveguide, there are also problems of the reflection loss due to the difference in refractive index between Si and Ge, and of the absorption loss caused by a metal electrode.

Abstract: A single-crystal layer of a first semiconductor material including single-crystal nanostructures of a second semiconductor material, the nanostructures being distributed in a regular crystallographic network with a centered tetragonal prism.

Abstract: A p-type semiconductor nanowire transistor is formed on the first semiconductor nanowire and an n-type semiconductor nanowire transistor is formed on the second semiconductor nanowire. The first and second semiconductor nanowires have a rectangular cross-sectional area with different width-to-height ratios. The type of semiconductor nanowires for each semiconductor nanowire transistor is selected such that top and bottom surfaces provide a greater on-current per unit width than sidewall surfaces in a semiconductor nanowire having a greater width-to-height ratio, while sidewall surfaces provide a greater on-current per unit width than top and bottom surfaces in the other semiconductor nanowire having a lesser width-to-height ratio. Different types of stress-generating material layers may be formed on the first and second semiconductor nanowire transistors to provide opposite types of stress, which may be employed to enhance the on-current of the first and second semiconductor nanowire transistors.

Abstract: A semiconductor structure includes an n-channel field effect transistor (NFET) nanowire, the NFET nanowire comprising a film wrapping around a core of the NFET nanowire, the film wrapping configured to provide tensile stress in the NFET nanowire. A method of making a semiconductor structure includes growing a film wrapping around a core of an n-channel field effect transistor (NFET) nanowire of the semiconductor structure, the film wrapping being configured to provide tensile stress in the NFET nanowire.

Abstract: Thermal mixing methods of forming a substantially relaxed and low-defect SGOI substrate material are provided. The methods include a patterning step which is used to form a structure containing at least SiGe islands formed atop a Ge resistant diffusion barrier layer. Patterning of the SiGe layer into islands changes the local forces acting at each of the island edges in such a way so that the relaxation force is greater than the forces that oppose relaxation. The absence of restoring forces at the edges of the patterned layers allows the final SiGe film to relax further than it would if the film was continuous.

Abstract: A planar or non-planar quantum well device and a method of forming the quantum well device. The device includes: a buffer region comprising a large band gap material; a uniaxially strained quantum well channel region on the buffer region; an upper barrier region comprising a large band gap material on the quantum well channel region; a gate dielectric on the quantum well channel region; a gate electrode on the gate dielectric; and recessed source and drain regions at respective sides of the gate electrode, the source and drain regions including a junction material having a lattice constant different from a lattice constant of a material of the buffer region. Preferably, the buffer region comprises a Si1-xGex material, and the junction material comprises one of a Si1-yGey material where y is larger than x, or pure germanium, or tin germanium.

Abstract: A method of fabrication of a metal oxide semiconductor field effect transistor is disclosed. At first, a substrate on which a gate structure is formed is provided. Afterward, a portion of the substrate is removed to form a first recess in the substrate at both ends of the gate structure. Additionally, a source/drain extension layer is deposited in the first recess and a plurality of spacers are formed at both ends of the gate structure. Subsequently, a portion of the source/drain extension and the substrate are removed to form a second recess in the source/drain extension and a portion of the substrate outside of the spacer. In addition, a source/drain layer is deposited in the second recess. Because the source/drain extension and the source/drain layer have specific materials and structures, short channel effect is improved and the efficiency of the metal oxide semiconductor field effect transistor is improved.

Abstract: Various source/drain stressors that can enhance carrier mobility, and methods for manufacturing the same, are disclosed. An exemplary source/drain stressor includes a seed layer of a first material disposed over a substrate of a second material, the first material being different than the second material; a relaxed epitaxial layer disposed over the seed layer; and an epitaxial layer disposed over the relaxed epitaxial layer.

Abstract: The present invention provides for nanostructures grown on a conducting or insulating substrate, and a method of making the same. The nanostructures grown according to the claimed method are suitable for interconnects and/or as heat dissipators in electronic devices.

Abstract: A method of fabricating a semiconductor device is disclosed that is able to suppress a short channel effect and improve carrier mobility. In the method, trenches are formed in a silicon substrate corresponding to a source region and a drain region. When epitaxially growing p-type semiconductor mixed crystal layers to fill up the trenches, the surfaces of the trenches are demarcated by facets, and extended portions of the semiconductor mixed crystal layers are formed between bottom surfaces of second side wall insulating films and a surface of the silicon substrate, and extended portion are in contact with a source extension region and a drain extension region.

Abstract: A manufacturing method for semiconductor device includes: forming an opening, in a surface of a semiconductor substrate being composed of first atom, the opening having an opening ratio y to an area of the surface of the semiconductor substrate ranging from 5 to 30%; forming an epitaxial layer in the opening, the epitaxial layer being made of a mixed crystal containing a second atom in a concentration ranging from 15 to 25%, and the second atom having a lattice constant different from a lattice constant of the first atom; implanting impurity ion into the epitaxial layer; and performing activation annealing at a predetermined temperature T, the predetermined temperature T being equal to or higher than 1150° C. and satisfies a relationship of y?1E-5exp (21541/T).

Abstract: A method to form a strain-inducing semiconductor region is described. In one embodiment, formation of a strain-inducing semiconductor region laterally adjacent to a crystalline substrate results in a uniaxial strain imparted to the crystalline substrate, providing a strained crystalline substrate. In another embodiment, a semiconductor region with a crystalline lattice of one or more species of charge-neutral lattice-forming atoms imparts a strain to a crystalline substrate, wherein the lattice constant of the semiconductor region is different from that of the crystalline substrate, and wherein all species of charge-neutral lattice-forming atoms of the semiconductor region are contained in the crystalline substrate.

Abstract: A photodiode in which a pn junction is formed between the doped region (DG) formed in the surface of a crystalline semiconductor substrate and a semiconductor layer (HS) deposited above said doped region. An additional doping (GD) is provided in the edge region of the doped zone, by means of which additional doping the pn junction is shifted deeper into the substrate (SU). With the greater distance of the pn junction from defects at phase boundaries that is achieved in this way, the dark current within the photodiode is reduced.

Abstract: A method for producing a High Temperature Thin Film Layer On Glass (HTTFLOG) of silicon, which is a precursor component of thin film transistors (TFTs). The invention described here is a superior method of fabricating HTTFLOG precursor structures or components for liquid crystal displays (LCDs) with quicker production time and lower cost of manufacture while enabling a groundbreaking increase in small and large screen resolution. This invention is a new sub-assembly intended for original equipment manufacturer (OEM) consumption and inclusion in display products.

Abstract: A semiconductor device exhibiting enhanced carrier mobility within a channel region of the semiconductor device is disclosed. The semiconductor device includes a gate stack having first and second sidewall spacers, where the gate stack is implemented above the channel region of the semiconductor device. The semiconductor device further includes first and second trenches formed adjacent to the gate stack, where the first and second trenches are conically shaped to be wider at a top portion of each trench as compared to a width of each trench below the top portion of each trench. The semiconductor device further includes strained silicon alloy formed within the first and second trenches, where a stress force exerted on the channel region of the semiconductor device is maximized at a surface of the semiconductor device below the gate stack.

Abstract: A semiconductor device including transistors and strain layers is provided. Each transistor includes a source region and a drain region on a substrate and a gate structure on a channel region between the source region and the drain region. Lengths of the channel regions of these transistors are the same, but at least one source or drain region has a width along a channel length direction and the width is different from widths of other source or drain regions. The strain layers include first and second strain layers embedded separately at two sides of each gate structure in the substrate. A first width of each first strain layer along the channel length direction is the same, and a second width of each second strain layer along the channel length direction is the same.

Abstract: A base structure for high performance Silicon Germanium:Carbon (SiGe:C) based heterojunction bipolar transistors (HBTs) with phosphorus atomic layer doping (ALD) is disclosed. The ALD process subjects the base substrate to nitrogen gas (in ambient temperature approximately equal to 500 degrees Celsius) and provides an additional SiGe:C spacer layer. During the ALD process, the percent concentrations of Germanium (Ge) and carbon (C) are substantially matched and phosphorus is a preferred dopant. The improved SiGe:C HBT is less sensitive to process temperature and exposure times, and exhibits lower dopant segregation and sharper base profiles.

Abstract: A multilayer semiconductor wafer has a substrate wafer having a first side and a second side; a fully or partially relaxed heteroepitaxial layer deposited on the first side of the substrate wafer; and a stress compensating layer deposited on the second side of the substrate wafer. The multilayer semiconductor wafer is produced by a method including depositing on a first side of a substrate a fully or partially relaxed heteroepitaxial layer at a deposition temperature; and at the same temperature or before significantly cooling the wafer from the deposition temperature, providing a stress compensating layer on a second side of the substrate.

Abstract: Semiconductor structures and devices including strained material layers having impurity-free zones, and methods for fabricating same. Certain regions of the strained material layers are kept free of impurities that can interdiffuse from adjacent portions of the semiconductor. When impurities are present in certain regions of the strained material layers, there is degradation in device performance. By employing semiconductor structures and devices (e.g., field effect transistors or “FETs”) that have the features described, or are fabricated in accordance with the steps described, device operation is enhanced.

Abstract: A field effect transistor with a heterostructure includes a strained monocrystalline semiconductor layer formed on a carrier material, which has a relaxed monocrystalline semiconductor layer made of a first semiconductor material (Si) as the topmost layer. The strained monocrystalline semiconductor layer has a semiconductor alloy (GexSi1-x), where the proportion x of a second semiconductor material can be set freely. Furthermore, a gate insulation layer and a gate layer are formed on the strained semiconductor layer. To define an undoped channel region, drain/source regions are formed laterally with respect to the gate layer at least in the strained semiconductor layer. The possibility of freely setting the Ge proportion x enables a threshold voltage to be set as desired, whereby modern logic semiconductor components can be realized.

Abstract: According to an example embodiment, a heterostructure bipolar transistor, HBT, includes shallow trench isolation, STI, structures around a buried collector drift region in contact with a buried collector. A gate stack including a gate oxide and a gate is deposited and etched to define a base window over the buried collector drift region and overlapping the STI structures. The etching process is continued to selectively etch the buried collector drift region between the STI structures to form a base well. SiGeC may be selectively deposited to form epitaxial silicon-germanium in the base well in contact with the buried collector drift region and poly silicon-germanium on the side walls of the base well and base window. Spacers are then formed as well as an emitter.

Abstract: A method for producing a wafer with a silicon single crystal substrate having a front and a back side and a layer of SiGe deposited on the front side, the method using steps in the following order: simultaneously polishing the front and the back side of the silicon single crystal substrate; depositing a stress compensating layer on the back side of the silicon single crystal substrate; polishing the front side of the silicon single crystal substrate; cleaning the silicon single crystal substrate having the stress compensating layer deposited on the back side; and depositing a fully or partially relaxed layer of SiGe on the front side of the silicon single crystal substrate.

Abstract: The invention relates to a method for forming a semiconductor heterostructure by providing a substrate with a first in-plane lattice parameter a1, providing a buffer layer with a second in-plane lattice parameter a2 and providing a top layer over the buffer layer. In order to improve the surface roughness of the semiconductor heterostructure, an additional layer is provided in between the buffer layer and the top layer, wherein the additional layer has a third in-plane lattice parameter a3 which is in between the first and second lattice parameters.

Abstract: A strain-inducing semiconductor alloy may be formed on the basis of cavities which may have a non-rectangular shape, which may be maintained even during corresponding high temperature treatments by providing an appropriate protection layer, such as a silicon dioxide material. Consequently, a lateral offset of the strain-inducing semiconductor material may be reduced, while nevertheless providing a sufficient thickness of corresponding offset spacers during the cavity etch process, thereby preserving gate electrode integrity. For instance, P-channel transistors may have a silicon/germanium alloy with a hexagonal shape, thereby significantly enhancing the overall strain transfer efficiency.

Abstract: The present invention provides a method for the controlled synthesis of nanostructures on the edges of electrodes and an apparatus capable of optical and electrochemical sensing. In accordance with the present invention, a method of fabricating nanowires is provided. In one embodiment, the method includes providing a substrate, creating a dielectric thereon, depositing a metal catalyst on the dielectric, patterning the metal catalyst, selectively etching dielectric, creating an electric field originating in metal catalyst, and applying a heat treatment. In another embodiment, the method includes providing a substrate, depositing a dielectric thereon, printing a metal catalyst on the dielectric and plastic substrate, printing silicide along the edges of metal catalyst, creating an electric field originating in metal catalyst; and applying chemical vapor deposition.

Abstract: A substrate material including a Si-containing substrate and an insulating region that is resistant to Ge diffusion present atop the Si-containing substrate. The substrate material further includes a substantially relaxed SiGe alloy layer present atop the insulating region, wherein the substantially relaxed SiGe alloy layer has a planar defect density from about 5000 defects/cm?2 or less. The substrate material may be employed in a heterostructure, in which a strained Si layer is present atop the substantially relaxed SiGe alloy layer of the substrate material.

Abstract: The present invention is directed to a transistor with an asymmetric silicon germanium source region, and various methods of making same. In one illustrative embodiment, the transistor includes a gate electrode formed above a semiconducting substrate comprised of silicon, a doped source region comprising a region of epitaxially grown silicon that is doped with germanium formed in the semiconducting substrate and a doped drain region formed in the semiconducting substrate.

Abstract: In a thin film transistor, a semiconductor layer containing Si and Ge is applied, a Ge concentration of this semiconductor layer is high at the side of the insulating substrate, and crystalline orientation of the semiconductor layer indicates a random orientation in a region of 20 nm from the side of the insulating substrate, and indicates a (111), (110) or (100) preferential orientation at the film surface side of the semiconductor layer.

Abstract: There is provided a method of producing a semiconductor wafer by thermally processing a base water having a portion to be thermally processed that is to be thermally processed. The method comprises a step of providing, on the base wafer, a portion to be heated that generates heat through absorption of an electromagnetic wave and selectively heats the portion to be thermally processed, a step of applying an electromagnetic wave to the base wafer, and a step of lowering the lattice defect density of the portion to he thermally processed, by means of the heat generated by the portion to be heated through the absorption of the electromagnetic wave.

Abstract: In a manufacturing flow for adapting the band gap of the semiconductor material with respect to the work function of a metal-containing gate electrode material, a strain-inducing material may be deposited to provide an additional strain component in the channel region. For instance, a layer stack with silicon/carbon, silicon and silicon/germanium may be used for providing the desired threshold voltage for a metal gate while also providing compressive strain in the channel region.

Abstract: In accordance with one or more embodiments, a semiconductor structure includes a semiconductor substrate, a first semiconductor material over the semiconductor substrate, and a second semiconductor material over a portion the first semiconductor material, wherein the second semiconductor material comprises silicon-germanium-carbon (SiGeC) and wherein the first semiconductor material is a silicon epitaxial layer. The semiconductor structure further includes an active device, wherein a portion of the active device is formed in the second semiconductor material and a dielectric structure extending from the first surface of the first semiconductor material into the semiconductor substrate through the first semiconductor material.

Abstract: Highly uniform silica nanoparticles can be formed into stable dispersions with a desirable small secondary particle size. The silican particles can be surface modified to form the dispersions. The silica nanoparticles can be doped to change the particle properties and/or to provide dopant for subsequent transfer to other materials. The dispersions can be printed as an ink for appropriate applications. The dispersions can be used to selectively dope semiconductor materials such as for the formation of photovoltaic cells or for the formation of printed electronic circuits.

Abstract: A device forming thin film for forming a semiconductor device; an inhibition portion that surrounds the device forming thin film and inhibits growth of a precursor of the device forming thin film into a crystal; a sacrificial growth portion that is formed by causing the precursor to sacrificially grow into a crystal, and is positioned around the device forming thin film separated by the inhibition portion; and a protection film that covers a top portion of the sacrificial growth portion and exposes a top portion of the device forming thin film are included. The protection film may be made of polyimide.

Abstract: A method for forming a transparent electrode on a visible light-emitting diode is described. A visible light-emitting diode element is provided, and the visible light-emitting diode element has a substrate, an epitaxial structure and a metal electrode. The metal electrode and the epitaxial structure are located on the same side of the substrate, or located respectively on the different sides of the substrate. An ohmic metal layer is formed on a surface of the epitaxial structure. The ohmic metal layer is annealed. The ohmic metal layer is removed to expose the surface of the epitaxial structure. A transparent electrode layer is formed on the exposed surface. A metal pad is formed on the transparent electrode layer.